'Fireflies', a track from his second album Ocean Eyes, climbs from seven to the top this week to end Jay Sean's chart reign.
Jason DeRulo holds steady at two with 'Whatcha Say', while Sean slips to three with the aptly-titled 'Down'.
Meanwhile, Beyoncé's 'Sweet Dreams' climbs from eleven to ten to become her 13th top ten hit as a solo artist.
Notable gains outside the top ten come from Ke$ha, who leaps from 55 to 22 with 'Tok Tok', and Chris Brown, who jumps from 27 to 24 with 'I Can Transform Ya'.
The top ten singles in full (click where possible for our reviews):
1. (7) Owl City: 'Fireflies'
2. (2) Jason DeRulo: 'Whatcha Say'
3. (1) Jay Sean ft. Lil Wayne: 'Down'
4. (3) Miley Cyrus: 'Party In The USA'
5. (4) Jay-Z ft. Rihanna, Kanye West: 'Run This Town'
6. (6) Lady GaGa: 'Paparazzi'
7. (9) Black Eyed Peas: 'Meet Me Halfway'
8. (5) Britney Spears: '3'
9. (8) Black Eyed Peas: 'I Gotta Feeling'
10. (11) Beyoncé: 'Sweet Dreams'